The fundamental principle of bitcoin is the anonymity and decentralized nature which empowers bitcoin to be able to empower the poor and makes it possible for money to be in the hands of the people. If Bitcoin becomes centralized then the principle is destroyed and there will be nothing like bitcoin again.Because bitcoin is decentralized is major reason why the government is fighting the it. The government wants to control bitcoin and as far as they can not arm twist bitcoin to control it the next move is to destroyed bitcoin which is where we are now. Centralized currency is being control by the central banks of the various governments making them the agents of government to carry out the government bidding.
That's my concern. If Bitcoin becomes centralized, then it would be nothing more than just a banking system controlled by the likes of governments worldwide. The huge dominance of mining hashrate from Bitmain would kill Bitcoin's decentralization in the long term, as no other company would be able to compete with it in the production of efficient ASIC miners. Bitcoin has already been heading towards centralization this way, but most people don't seem to care if they're able to make money with it.
However, I believe that decentralization is one of the key aspects of blockchain technology, as it allows a cryptocurrency to remain immutable and resilient against 51% attacks. Perhaps, if Bitcoin devs would pay close attention towards the imminent threat of centralization within the Bitcoin network, then the cryptocurrency would be much more accessible to ordinary people just like it was in the good old days. A quick change in the PoW algorithm or a new mechanism that would prevent mining pools from emerging would be ideal, as it would allow Bitcoin to remain as decentralized as possible.
Therefore, if Bitcoin remains decentralized no matter what, it would pass the test as a truly immutable cryptocurrency free from government manipulation, corporate interests (Bitmain), and more. While there's no system that's 100% decentralized, it's best to preserve decentralization as much as possible. ASIC resistance might be the key to true decentralization, although the same scenario could happen with GPU mining where a single company controls most of the hashrate. Yet, it's best to balance between both PoW and PoS (hybrid model?) to allow the cryptocurrency to stay as decentralized as possible while maintaining unparalleled security. Just my thoughts